Various types of hearing prostheses may provide persons with different types of hearing loss with the ability to perceive sound. Hearing loss may be conductive, sensorineural, or some combination of both conductive and sensorineural hearing loss.
Conductive hearing loss typically results from a dysfunction in any of the mechanisms that ordinarily conduct sound waves through the outer ear, the eardrum, or the bones of the middle ear. Persons with some forms of conductive hearing loss may benefit from hearing prostheses such as acoustic hearing aids, bone anchored hearing aids, and direct acoustic cochlear stimulation devices.
Sensorineural hearing loss typically results from a dysfunction in the inner ear, including the cochlea where sound vibrations are converted into neural signals, or any other part of the ear or auditory nerve, that may process the neural signals. Persons with some forms of sensorineural hearing loss may benefit from hearing prostheses such as cochlear implants and auditory brain stem implants.
Depending on the severity of the sensorineural hearing loss, some persons may benefit from using a hybrid prosthesis in one ear (e.g., a combined acoustic hearing aid with a cochlear implant). Persons may also benefit from using different prostheses in each ear (e.g., an acoustic hearing aid in one ear and a cochlear implant in the opposite ear). Using separate hearing prostheses may sometimes be referred to as bimodal hearing because the prosthesis recipient is hearing in two modes, e.g., acoustically and electrically in the case where the two prostheses include an acoustic hearing aid and a cochlear implant.
The effectiveness of a hearing prosthesis depends not only on the design of the prosthesis itself but also on how well the prosthesis is configured for or “fitted” to a prosthesis recipient. The fitting of the prosthesis, sometimes also referred to as “programming” or “mapping,” creates a set of configuration settings and other data that define the specific characteristics of the signals (acoustic, mechanical, or electrical) delivered to the relevant portions of the person's outer ear, middle ear, inner ear, or auditory nerve. This configuration information is sometimes referred to as the recipient's “program” or “MAP.”